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Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders

X-ray linear dichroism (XLD) is a fundamental property of many ordered materials that can for instance provide information on the origin of magnetic properties and the existence of differently ordered domains. Conventionally, measurements of XLD are performed on single crystals, crystalline thin fil...

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Autores principales: Hageraats, Selwin, Thoury, Mathieu, Stanescu, Stefan, Keune, Katrien
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8284400/
https://www.ncbi.nlm.nih.gov/pubmed/34212872
http://dx.doi.org/10.1107/S1600577521004021
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author Hageraats, Selwin
Thoury, Mathieu
Stanescu, Stefan
Keune, Katrien
author_facet Hageraats, Selwin
Thoury, Mathieu
Stanescu, Stefan
Keune, Katrien
author_sort Hageraats, Selwin
collection PubMed
description X-ray linear dichroism (XLD) is a fundamental property of many ordered materials that can for instance provide information on the origin of magnetic properties and the existence of differently ordered domains. Conventionally, measurements of XLD are performed on single crystals, crystalline thin films, or highly ordered nanostructure arrays. Here, it is demonstrated how quantitative measurements of XLD can be performed on powders, relying on the random orientation of many particles instead of the controlled orientation of a single ordered structure. The technique is based on a scanning X-ray transmission microscope operated in the soft X-ray regime. The use of a Fresnel zone plate allows X-ray absorption features to be probed at ∼40 nm lateral resolution – a scale small enough to probe the individual crystallites in most powders. Quantitative XLD parameters were then retrieved by determining the intensity distributions of certain diagnostic dichroic absorption features, estimating the angle between their transition dipole moments, and fitting the distributions with four-parameter dichroic models. Analysis of several differently produced ZnO powders shows that the experimentally obtained distributions indeed follow the theoretical model for XLD. Making use of Monte Carlo simulations to estimate uncertainties in the calculated dichroic model parameters, it was established that longer X-ray exposure times lead to a decrease in the amplitude of the XLD effect of ZnO.
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spelling pubmed-82844002021-08-02 Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders Hageraats, Selwin Thoury, Mathieu Stanescu, Stefan Keune, Katrien J Synchrotron Radiat Research Papers X-ray linear dichroism (XLD) is a fundamental property of many ordered materials that can for instance provide information on the origin of magnetic properties and the existence of differently ordered domains. Conventionally, measurements of XLD are performed on single crystals, crystalline thin films, or highly ordered nanostructure arrays. Here, it is demonstrated how quantitative measurements of XLD can be performed on powders, relying on the random orientation of many particles instead of the controlled orientation of a single ordered structure. The technique is based on a scanning X-ray transmission microscope operated in the soft X-ray regime. The use of a Fresnel zone plate allows X-ray absorption features to be probed at ∼40 nm lateral resolution – a scale small enough to probe the individual crystallites in most powders. Quantitative XLD parameters were then retrieved by determining the intensity distributions of certain diagnostic dichroic absorption features, estimating the angle between their transition dipole moments, and fitting the distributions with four-parameter dichroic models. Analysis of several differently produced ZnO powders shows that the experimentally obtained distributions indeed follow the theoretical model for XLD. Making use of Monte Carlo simulations to estimate uncertainties in the calculated dichroic model parameters, it was established that longer X-ray exposure times lead to a decrease in the amplitude of the XLD effect of ZnO. International Union of Crystallography 2021-05-19 /pmc/articles/PMC8284400/ /pubmed/34212872 http://dx.doi.org/10.1107/S1600577521004021 Text en © Selwin Hageraats et al. 2021 https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
spellingShingle Research Papers
Hageraats, Selwin
Thoury, Mathieu
Stanescu, Stefan
Keune, Katrien
Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title_full Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title_fullStr Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title_full_unstemmed Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title_short Soft X-ray nanospectroscopy for quantification of X-ray linear dichroism on powders
title_sort soft x-ray nanospectroscopy for quantification of x-ray linear dichroism on powders
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8284400/
https://www.ncbi.nlm.nih.gov/pubmed/34212872
http://dx.doi.org/10.1107/S1600577521004021
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